The CAS Registry Mumber 17082-89-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,7,0,8 and 2 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 17082-89: (7*1)+(6*7)+(5*0)+(4*8)+(3*2)+(2*8)+(1*9)=112 112 % 10 = 2 So 17082-89-2 is a valid CAS Registry Number.